Apparatus for metal casting



Jan. 20, 1942. RD 2.270.340

APPARATUS FOR NIEI'IMLJ CASTING Filed Aug. 5, 1940 3 Sheets-Sheet 1 InveMwR:

PERCY PRITCHARD 1942- P. PRITCHARD 2,270,34 0' APPARATUS FOR METAL CASTING Filed Aug. 5, 1940 3 Sheets-Sheet 2 1942- P. PRlTCHARD APPARATUS FOR METAL CASTING 3 Sheets- Sheet 3 Filed Aug. 5, 1940 Iweuron PERCY PKITCHARP W PWTORNEY partoi the die.

. drawings.

Patented Jan. 20, 1942 UNITED STATE s PATENT orncr:

APPARATUS non iun'mr. cAsTmo. Percy Pritchard, Barnt Green, England 1 Application August 5, 1940, Serial No. 351,514 I In Great Britain August 19, 1939 7 Claims. Theinvention relates to apparatus for the 1 castingof metals under pressure.

An object of the invention is to bring the die,

or a partto completea die, above a container 3 for liquid metal such as a furnace in the proper relationship :for forcing the metal up into the die under fluid pressure and to remove the die or part of the die therefrom after casting and turn it over in the course of removal so that its interior is more readily accessible.

, Another objectiis to provide an arrangemen of multiple levers or arms in pivotal relation withthe die or die part and with a source of power by which they maybe operated to move the die or die part and turnit over in the process I of moving it to or from the fumaceor container for liquid metal.

.Anotherobject is to combine with such means for swinging and positioning a die, power means on which the furnace or container for liquid metal is arranged andby which tight closure against the die can be effected.

Another object is toprovide power means for operating latching and stripping means for connecting the die to the furnace and. separating parts of the die after the casting operation.

M .In one preferred construction the-furnace having a pot for containing liquid metal is mounted on a'vertically moving pneumatic or hydraulic cylinder.

Aroll over platen or frame platenin position ready to commence the actual casting operation. r

Figure 4 shows a similar view to Figure 3 with v {the die parts separated in the Position to which they would bemoved after the castingoperation .the cylinder. The arms 6 are; arranged one on each side of the machine keyed. to'the shaft 1 and carry in pivotal bearings 8a roll over platen 9. The platen has side members to which are also pivoted at l3 to the free ends of a pair of arms II that are freely pivoted at 12 toithe cylinder. The arms 6 act as drivers and the arms II as followers which, owing to the fact that they are pivoted about different centres from the is carried at each end thereof bytwo arms piv- 1 oted about different centres and operated hy- 1 draulically and/or pneumatically so that they can be swung from an approximately horizontal position in which the platen is away from the furnace to a position in which the platen is inverted and held above the iumace. The top part ofthe die is bolted to this platenwhich also carries a hydraulic cylinder for operating ejector plungers and mechanism which enter the top One preferred construction in accordance with theinvention is illustrated in the accompanying Figure 1 shows an elevation in part section of the apparatus with the rollover platen carrying a die part in its position remote from the furnace ready for inspection. v

Figure 2. shows a similar view to Figure 1 with the roll over platen above the furnace andthe furnace forced down by the ejector mechanism to separate the die parts.

Figure 3 shows a sectional view of the furnace container, die parts and part of the roll over arms 6, cause the platen 9 toroll over when the arms 6 are operated asindicatedby the chain dotted lines in Figure 1. A table I! is provided to support the platen in the open position of the dies and the platen carries "a hydraulic cylinder l5 mounted on a die casing l9 .by means of'the. three pillars l5 which casing is secured to the platen. The ram of this'cylinder (see Figure 3) is connected by the Pillars H to. a member l8 which slides in the. die casing 19 and which is adapted to carry ejector rods .20or other means for ejecting the casting from the die. The upper part of the die 2| is bolted to the platen through the intermediary of the die casting l9 and the lower part of the die 22 is carried by the furnace n It is preferable to usean open ended pct 23 as the container for the liquid metal and toplace on this a lid having a nozzle or spout 25 which is enlarged at itsfupper end sothat its cross'section bears the correct :relation to the adjacent cross sections of the casting to ensure efiicient feeding. M It is then preferable to mount the lower part of the die 22 on top of and in contact with the lid 24.

In the drawings the die is shown for making a complicated circular casting from an aluminum or other light metal alloy." 1

A sand core 28on a metal carrier 35 is also placed in position on the pillar part 36 of the die and secured by a locking pin 31. The open metal container" is filled with liquid metal and lowered into the furnace or if already in the furnace is filled with liquid metal from a ladle. The lid 24 and feeding nozzle 25 and the lower part 22 of the die are then placed on the container or pot with the interposition or suitable asbestos jointing washers 38. The fluid-pressure means 4, 5

, arenow operated to swing the arms 6 carrying the platen 8 so that the platen is turned over to bring the die on its underside and into a position accurately located above the furnace as shown in Figure 2. The furnace is raised by means of its fluid pressure cylinder to bring the two parts 2| and 22 of the die into contact and clamp them together, while suitable hydraulic or pneumatic locking bolts .39 are shot to hold the two die parts together and to secure the lower part 22 of the die to the furnace 3, as shown in Figure 3. Dowels 40 or other suitable guiding means may be provided to ensure the accurate relative location of the die parts.

The casting'is now made preferably by means of compressed airforced into the metal container through the inlet 42, which forces the metal up the nozzle into the die. As soon'as the casting has set the pin 31 which holds the core is released and the ejector cylinder I5 is energised to project a number of plungers which bear on the casting and also on the lower part of the die,

lease to the and so separate the two die parts It and 22 and I eject the casting from the upper part of the die 2| as shown in Figure 2. This movement is possible dueto the fact that the pressure exerted by the ejector cylinder I5 is greater than that exerted by the cylinder l supporting the furnace '3-so that the ejector cylinder is able to force the casting in the lower part of the die and the furnace downwards.

In certain cases, as for instance, when the upper partof the casting contains a number of parts such as fins of small cross sectional area, and the lower part is of large cross sectional area, the upper part may require to be ejected from the die after a comparatively short time in order to avoid setting up contraction stresses between itself and the die, whereas the lower part of the casting may require a much longer period to enable the mould to be fed slowly.

with the previously known apparatus the cast ing would have who made and ejected in a time which isv only a compromise between these two requirements. Withthe presentapparatus it is possible to eject the upper part ofthe casting from the upper part of the die before the lower part of the casting has been finished, since the lower part of the die is still firmly pressed into contact with the furnace the metal can continue to be fed under pressure from the furnace into this lower part-of the die, provided asufficient mass of'metalhas already set in its upper part to form a seal.

'After'the casting has been finished and ejected from. the upper part of the die the furnace is lowered to the position shown in Figure 4, the platen with this upper part of the die may then be swungiba'c to the position shown in Figure 1 leaving the .casting with its sand core in the lower part of'the die on top of the furnace from which it is subsequently removed.

Since all these operations apart from cleaning or assembling the die, attaching the core and refilling or replacing the container are done by Y hydraulic or pneumatic means, the apparatus can be conveniently controlled from a remote control cabin, not shown, or other place shielded from the casting apparatus and the process merely consists of operating a series of valves in the right sequence at the right speed and for the right duration.

This is illustrated diagrammatically in Figure 2 which shows the grouped control valves and the various leads from these valves to the apparatus. Oil under pressure is supplied by the pipe 50 and is led via the control valve 5| and the lead 52 t0 the cylinder 4 operating the throw over arms, on release the oil from the lead 52 is returned to theisump via the lead 53. The raising or lowering of the furnace is done hydraulically, being controlled by the valve 54 and supplied via the lead 55, the release to the sump being via lead 56. The hydraulic power is also used to operate the ejector 15. It is controlled by valve 51, the lead 58 causing a downward or ejecting movement of the ram and the lead 59 the return or upward movement: while the lead 60 is the reump. Compressed air from the main 6| can be admitted by the valve 52 to the lead 63 to shoot the locking bolts and secure the two halves of the mould and is admitted to'the lead 64 to withdraw the bolts in each case the exhaust is to atmosphere via the lead 65. In a similar way valve 66 controls the bolts to secure the lower half of the mould to the furnace. The lead 61 is for shooting the bolts, the lead 68 for withdrawing them and the lead 69 for exhausting to atmosphere. Compressed air from mains, a receiver or other device is admitted by the valve 10 to the lead 42 which takesit to the container 23 to force the metal into the mould the pressure being read on the manometer H. The valve 12 is for exhausting the lead 42 to atmosphere. The operation can be facilitated either by combining or interlocking the controls of these valves or by providing an indicator device which is worked in conjunction with the valves and which shows by means of pilot lights which valve is to be operated next. This simplification of the operation of the apparatus enables it'to be operated rapidly and easily even by comparatively unskilled workmen, thus efiecting a very considerable economy, both in time and wages.

I claim:

1. Apparatus for casting metals by fluid pressure comprising a container in which metal can be maintained liquid, means adapted to carry a die or part of a die, said means being movable from a position in which the die is remote from the container and m inverted position to a position in which the die is above the container, said means being operable to turn the die to upright position during such movement,.and means for bringing the die and container together and holding them tightly in contact during the casting process.

2. Apparatus for casting metals by fluid pressure, comprising a heating furnace adapted to receive a pot of metal, means for moving the furnace upwardly and downwardly, means supporting a die, said means being movable from a position in which the die is remote from the furnace and inverted to a position in which the die is above the furnace, said means being operable totum the die upright during such movement.

3. Casting apparatus comprising a heating furnace in which a pot containing liquid metal can be placed, a die part, means supporting the die part and operable to move it into a position above the furnace, means for moving the die and furnace toward each other, means for holding said die parts together, pressure means for forcing metal from the potinto the die, and means for ejecting the finished casting from the die part,

said means for ejecting the casting having sufficient force to overcome the means which hold together the two die parts.

4. Apparatus for casting metals by fluid'pressure comprising a heating furnace, means for raising and lowering the furnace, pivoted arms supporting a member to which a die part can be attached, means for moving the pivoted arms from a substantially horizontal position in which the member supported thereby-is removed from the furnace to a substantially vertical position in which said member is positioned vertically above the furnace, said arms being so connected to the member that the member is turned over as the arms are moved from their horizontal to their vertical position.

5. Apparatusfor casting metals by fluid pressure comprising a heating furnace, a vertically arranged'pneumatic or hydraulic cylinder having vertically arranged power cylinder beneath the furnac having a piston by which the furnace canbe raised or lowered, a die-supporting member carried at the ends of two arms which are pivotally supported adjacent the furnace at their other ends, power means for swinging the arms from an approximately horizontal position in which the die-supporting member is removed from the furnace and is inverted to a position in which said member is positioned above the furnace adjacent a second die part, means for turning said member to upright position during such movement, means for supplying fluidunder pressure to said pot to cause liquid metal therein to be forced into the die, power operated means 2 carried by the die-supporting member, and ejeca piston connected to the furnace by which the furnace can be raised or lowered, a platen supporting a die part and carried at the ends of two arms which are pivotally supported adjacent the furnace at their other ends, pneumatic or hydraulic means for swinging th arms from an approximately horizontal position in which the platen is removed from the furnace to a position in which the platen is above the furnace in a position adjacent a second die part, a third armconnected at its one end to the platen and pivoted at its other end adjacent the furnace at a point spaced from the pivotal supports of the two firstmentioned arms, said third arm being operable to invert the platen during. said movement of the platen, and a hydraulic cylinder carried by the platen and having power operated means to which ejector rods are attached, said ejector rods being operable by the cylinder to separate the die parts for the removal of the casting therefrom.

6. Apparatus for casting metals by fluid pressure comprising in combination a heating furnace, a pot therein for containing liquid metal, a

tor rods attached to said power operated means and being adapted to separate the die parts for the removal of thecasting.

7. Apparatus for casting metals by fluid pressure. comprising in combination a heating furnace, a removable pot in said furnace adapted to contain liquid metal, a vertically arranged power cylinder having, a' piston connected to the furnace whereby the furnace may be raised or lowered, a die-supporting platen, two arms having their one endspivotally connected to the platen and their other ends pivotally supported adjacent the furnace, power means for swinging the arms from an approximately horizontal position in which the platen is removed from the furnace to a position in which the platen is above the furnace and adjacent a second die part,

means for inverting the platen during such movement, power operated means carried by the platen to which ejector rods are attached and which are operable to separatethe die parts for removing the casting therefrom, means for supplying fluid under pressure to said pot to force liquidmetal therefrom to the die, and a cover for said pot which carries a delivery nozzle depending into the pot, said cover supporting said second die part.

' PERCY PRITCHARD. 

